1. Field of the Invention
This invention relates to an apparatus for machining and statically balancing a large and heavy workpiece, and more particularly to an apparatus of the aforesaid type which includes a high capacity turntable on which the workpiece is mounted for rotation past a stationarily-mounted machining tool, and in which the apparatus also includes a self-contained drive package for the turntable and a balancing cylinder, whereby the workpiece may not only be machined while mounted on the turntable but may also be statically balanced subsequent to the machining operation without being removed from the turntable. The invention will be described in connection with the machining and balancing of the extremely heavy and large runner of a hydraulic turbine. Such a runner typically might have a weight of 450 tons, and a physical size such as 9.9 meters in diameter and a height of 5.6 meters. However, the apparatus of the invention is not necessarily restricted to use in the machining and static balancing of hydraulic turbine runners, but may be used for the machining and static balancing of other types of workpieces. The apparatus of the invention may be used in connection with the machining and static balancing of new units, and also in connection with the repair of old units which require machining and/or static balancing.
The apparatus for machining and statically balancing a workpiece as will be hereinafter described is particularly useful for use in machining and statically balancing an extremely large workpiece such as the runner of a hydraulic turbine, for example, which is too large and heavy for construction, machining and balancing all in one piece at a manufacturing site which may be far distant from the site of its intended use, and which therefore requires that a plurality of pieces manufactured at the factory be fabricated into a unitary member at or near the site of its intended use, with the fabricated unitary member also being finish machined and statically balanced at or near the site of its intended use.